The massive Rim Fire burning in and around California’s Yosemite National Park is now the largest U.S. wildfire in 2013 and currently the nation’s top priority as many residents remain evacuated as of Saturday morning (31-August).

As of Sat evening, Inciweb is reporting the Rim Fire is 222,777 acres and 40% contained with over 5,000 personnel battling the blazes, and officials are projecting they may have full containment by late September.

Unfortunately this beast is human-caused and, although investigators have not determined the official cause yet, a local Fire Chief has indicated it may be the result of illegal pot growers.

According to National Parks Service Fire and Aviation Mgmt, as many as 90% of wildland fires in the U.S. are caused by humans. Some human-caused fires result from…

campfires left unattended

burning of debris

negligently discarded cigarettes

off-road vehicles

firearms + exploding targets

intentional acts of arson

The remaining 10% are started by lightning or lava. In addition, wildfires caused by lightning burn an average of 5.5 million acres annually.

Acreage burned comes from a variety of factors…

climate shift to a hotter, drier West after decades of cooler weather

pine beetle infestations that create more fuel to burn

decades of fire suppression

Even though it seems like much of the western U.S. is burning, the National Interagency Fire Center reports 34,388 fires have burned almost 3.8million acres in the U.S. from January 1 – August 31, 2013 … which is well below the 10 year average of 54,072 fires that burned 6million acres for this same time period.

Below are some amazing shots of the Rim Fire and the incredible Hotshots and firefighters working the front lines…

View From Pilot Peak Lookout / Credit: USFS-Mike McMillan

The National Park Service (NPS) fire crew is helping to protect the Giant Sequoias in Tuolumne Grove, about 16 miles (26 km) west of Yosemite Village on Tioga Pass Road in Yosemite National Park. Credit: USFS

Fire Crews construct fireline / Credit: USFS-Mike Mcmillan

Silver State IHC on South Flank / Credit: USFS-Mike McMillan

Credit: USFS

Credit: USFS

Melted Power Meter / Credit: USFS-Mike McMillan

Please review and share some safety resources from our partners at U.S. First Responders Association…